Thermal relay



March 2l 1933.

J. E; WILLING THERMAL` RELAY Filed June 2s, 1930 Z0 M TTORNEY VENTORv Patented 21,1933v UNITED STATES PATENT OFFICE JOSEPH E. WILLING, 0I' ROCHESTEBLN'EW YORK, .ASSIGNOB TO GENERAL RAILWAY SIGNAL COMPANY, 0F ROCHESTER, NEW YORK t -y THERMAL RELAY Application led June 26,

This inventionrelates in general to relays, and has more particular reference to a thermal relay with special adjusting features for adjusting for changes of voltage and for varying the timing of operation of the relay.

Among the objects of the present invention is to provide a thermal relay which can-be readily adjusted for changes of voltage, so as to maintain the timing of relay operation practically constant. i

Another object is to provide a thermal relay which can be readily adjusted to give various times of operation.

A further obj ect is Ato provide an adjustable resistance element therein which is simple in construction, but is unusually securely maintained in proper operative position, and at the same time is very economical to manufacture.

Further objects include decreasing the cost of production, increasin the eiciency, and prolonging the useful li e, of devices of the character in question.

Further objects, purposes and characteristie features will appear as the description progresses, reference being made to the aceompanying drawing, showing, solely by way of example, and in no manner in a limiting sense, one form which the invention can assume. In the drawing Fig. 1 is a top plan view of a relay in accol-dance with this invention.

Fig. 2 is a sectional view on linef2-2 of Fi 1, viewed in the direction of the arrows.

ig. 3 is a sectional view on line 3 3 of Fie'. 1, viewed in the direction of the arrows.

ig. 4 is a fragmentary sectional view, on line 4 4 of Fig. 3, viewed in the direction of the arrows.

Fig. 5 is a circuit diagram showing the invention.

The relay forming the subject matter of the present invention is of very general use, and particularly so in railway practice, for insuring a predetermined lapse of time between two operations which bear the relation of cause and effect toeach other:

The relay can, for example, be used in controlling switch machines and the like in connection with approach locking.

Referring now to the drawing, in the em- 1930. Serial No: 463,903.

bodiment shown the relay comprises a transparent case TC, having a top plan TP of insulating material clamped to the case' by means of bolts b passing through the top plate and a portion of a suspending bracket per ends to the terminal post 2. The brass strips are positioned to face each other, with the two arms parallel but spaced a short distance from each other as shown, whereby a uniform increase of temperature of the two arms causes them to tend to separate from each other at the .lower ends, while a like decrease in temperature causes the lower ends to attempt to draw together'. The lower ends are anchored together by means of a plate 12 whereby changes of temperature which affect the two arms equally can have no effect on moving the thermal element TE as a whole. The thermal element carries an insulating block 13 to which are fastened two Contact points 14 and 15, insulated from each other by the block and respectively connected up with the terminal posts 5 and 6. v

Carried on one of the arms of the thermal element, as arm 8, is a heating winding 16, which, when energized causes its arm to move the entire thermal element to the left, in the case shown in the drawing, as viewed in Fig. 2, to thereby break the back contact 15 and make the front contact 14, the thermal element being positioned between xed back and front contacts 17 and 18 respectivel carried by the terminal posts 7 and 3. n deenergizing the heating winding, the thermal element slowly returns to its original posiliion in which it makes up the back contact In order to adjust the time required for operation of the thermal element, and also to adjust for changes in applied voltage in the heating coil, an adjustable resistance element AR is pro 'ded.

tion to the top plate as by means et nuts on binding post 1. Pinned to the rod 19 is a thumb nut 24 for turning the rod within its tubular member, and thereby causing the traveler nut and arms to move along the threaded portion 20, the thumb nut having a seai 25 for 'fastening it to a stop plate 26, in any desired position by means of a series of apertures 26l in plate 26. Plate 26 is keyed to the tubular member 23 and held in itsk keyed position by means or a dished spring washer 27 received in a socket in the thumb nut. W ith this arrangement of parts, when the' thumb nut 24 and lock plate 26' are interconnected it is impossible to turn the threaded rod and hence it is impossible to move the traveler.

Carried by the post 4 is ya rod 28, with a porcelain sleeve 29 received thereon and held in place by nuts 30. The porcelain sleeve has its outer surface threaded to form teeth 31 for receiving a resistance Wire 32v which is wound in the teeth, as shown best vin Fig. 4. -This construction insures that the resistance winding, even though it expands on being heated by current traversing 1t, will remain securely in place, and also facilitates the operation of winding the resistance wire and hence decreases the cost of manufacture :very materially. The resistance wire is fastened at its upper end to a clamp 33 which is electrically connected by a wire 34 to the binding post 35 at the lower end of the heating coilv 16, with the upper' end of the heating coil 16 connected by wire 36 to the terminal post 2.

The spring arms 22 on the traveler embrace the resistance winding 32 on opposite sides by means of their inturned spring fingers 221 whereby to vary the resistance inserted in the ener 'zing circuit for the heat- .ing winding 16, t e resistance increasing or decreasing according as the fingers move away or toward the clamp 33.

With the structure described above, it is seen that a thermal relay has been provided which has a thermal element comprising two spaced parallel bi-metallic arms anchored at =to prevent relative movement therebetween,

a eir upper ends to a fixed support, and havlng their lower free ends connected together whereby to compensate for changes in room temperature, together with readily adjustable means for varying `the energization of a heating winding on one of the two bi-metallic as enclosed Within a dashed line rectangular.

Together with the thermal relay TR, is a. relay M, which can be operated either manually or automatically in any desired manner to pick up its contact .finger when so energized, a stick relay'L, and a device P, which can be a relay or any desired device which it is desired tcl energize a predetermined time after the operation of relay M. Relay M, for example, can be automatically controlled in accordance with trafiic conditions, while the device P can be a relay which controls the operation of a. switch machine or like mechanism. i

1n the arrangement of parts shown in Fig. 5, on energization of relay M, itscontact finger is picked up to thereby energize theheating winding of the thermal relay, through a circuit including C, contact finger 37 and front point of relay M, wire 38, contact finger 39 and back point of L, Wire 40, resistance 32', Wire 34, heating Winding 16, wires 4l and 42, to- B. On energization of the heating winding 16, the thermal element moves to open its back contact 15 and close its front contact 14 whereupon the stick relay L is energized through a circuit including C, contact finger 37 and front point of M, relay L, wire 43, Contact finger 14 and front point of TR, and wire 44 to B. On being picked up, the stick relay L is stuck up through a circuit including, C, contact finger 37 and front point, relay L, contact finger 39 and front point, wire 40, etc., as above,

throu h the heating winding 16 to B.

It s ould be noted that onl relay L picking up, the energizing circuit for the heating element through a back point of L, previously referred to, is broken, and a new one is established which includes the windin of relay L, and this winding is of such hg resistance as to so decrease the current passing through the heating winding as to allow the heating point of relay L, and the back point 15 of the .thermal relay TR, whereby it requires, for energization, that the thermal relay pass through a complete cycle of operation and returns to its initialposition. The thermal relay must close its front point 14 to pick up By arranging the various parts as just de-` scribed, so that the time interval elapsing between the o ration of an operating member as M, an that of an operated member, as l), is equal to the time required for the thermal relay to move from its back point to its front point, and back again to its back point, it is assured that the thermal relay shall always beready for a successive operation, no matter how closely the successive o rations follow each other. This is-not t e casewhere the time interval is determined onlyby the movement of a thermal element from one position to an opposite osition, as a considerable time is required gbr the element to return to its initial position so that an attempted successive operation during the return period of the thermal element, necessarily fails.

The above rather specific description of one form of the resent invention is given solely by way of illustration, and is not intended, m any manner whatsoever, in a limiting sense. Obviously, the invention can assume many dierent physical forms, and is susceptible of numerous modifications, and all such forms and modifications are intended to be included in this application, as come. within the scope of the appended claims.

Having described my invention, I now claim 1.- In a thermal relay, in combination, fixed front and back points, and a thermal element positioned to move between said points and including, spaced, bi-metallic arms, a heating coil on but one of said arms, and a rheostat for regulating flow of current through the heating coil.

2. In a thermal relay, in combination, fixed front and back points, a thermal element positonedto move between said points and including, s aced, bi-metallicarms, a top plate for the re ay, one end of each. arm being anchored to the to plate, means restraining the l other ends of. t e arms to move together, a

heatin coil on the unanchored end of but one of sai arms, and a rheostat for regulating flow of current through the heating coil.

3. In a thermal relay, in combination, iixed front and back points,.a thermal element po'- sitioned to move between said points, and infor regulating flow of current throuilliethe cluding spaced, bi-metallic arms, a heating coil on but one of said arms, and a rheostat heating coil, said rheostat including a aded spindle of insulating material, and a resistance wire wound in-v the threads of the spindle.

4. In a thermal relay, in combination, fixed front and back points, and a thermal element.

positioned to move between said pointsiland including, spaced, bi-metallic arms, eating coil on but one of said arms, and a rheostat for regulating flow of current through the heating coil, said rheostat including a threaded spindle of insulating material, a resistance wire wound in the threads of the spindle, a threaded carrier slidable along the resistance wire, and a screw for moving said carrier.

5. In a thermal relay, in combination, fixed front and back points, a thermal element positioned to move between said points, 'andv including spaced, lai-metallic arms, a heating` coil on ut one of said arms, and a rheostat for regulating flow of current through the heating coil, said rheostat including a threaded spindle of insulating material, a resistance wire wound in the threads of the spindle, a threaded carrier slidable along the resistance wire, a screw for moving said carrier, and apertured members fixed respectively to the top plate andfthe screw for locking the screw in any one of a' plurality of adjusted positions. f

.6.v In a thermal relay, in combination; a top plate, fixed front and back contacts, a thermal element having contacts movable between the fixed contacts and including spaced bi-metallic arms anchored at one end to the top plate and positioned to move in opposite vdirections upon changes in temperature,

means restraining the unanchored ends of the arms to move together, a heating coil on one of the arms, a circuit for energizing the heating coil, and a variable resistance in said circuit comprising a fixed stud, a threaded insulating sleeve on the stud, resistance wire in the threads of the sleeve, and a contact slidable over the resistance wire.

In testimony whereof I afix mv signature.

` JOSEPH E. WILLING.

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